1. Field of the Invention
This invention relates to power supply systems and particularly to a power supply that reduces the effects of sidebands in an RF signal unit caused by spectral lines at the power supply switching frequency.
2. Description of the Prior Art
In conventional power supply arrangements, supplying power to units that amplify an RF carrier, rectified power is applied to a pulsed or switched switching regulator, converted into a chain of pulses and then after passing through a suitable power transformer is rectified and filtered to provide the regulated voltage source for the RF carrier unit. The power supply switching frequency is normally a stable fixed frequency. However, the switching fundamental frequency and its harmonics create a residual noise level after mixing with the RF carrier even after passive and active filtering in the power supply. The extraneous or switching frequency signal frequency and amplitude modulates the RF signal and its sidebands to a degree that causes noticeable sidebands offset from the RF signal and sidebands thereof by the switching frequency. Thus, for example, in a doppler radar system the sidebands resulting from the switching frequency may cause undesired detection of target signals in the doppler filters. It would be a substantial advantage to the art if a switched or pulsed power supply were provided that eliminated the undesirable effects of switching frequency on an RF carrier and its sidebands.